21492547 has 2 divisors, whose sum is σ = 21492548. Its totient is φ = 21492546.

The previous prime is 21492533. The next prime is 21492551. The reversal of 21492547 is 74529412.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21492547 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21492577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10746273 + 10746274.

It is an arithmetic number, because the mean of its divisors is an integer number (10746274).

Almost surely, 2^21492547 is an apocalyptic number.

21492547 is a deficient number, since it is larger than the sum of its proper divisors (1).

21492547 is an equidigital number, since it uses as much as digits as its factorization.

21492547 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 34.

The square root of 21492547 is about 4636.0055004281. The cubic root of 21492547 is about 278.0327541070.

The spelling of 21492547 in words is "twenty-one million, four hundred ninety-two thousand, five hundred forty-seven".